Many households outside of urban or suburban areas are not connected to public drinking water systems. Instead, they depend on water supplied by a well. Typically, a submersible pump in the one horsepower range is submerged in the well and used to pump water from the well up to a house or other site. Nonsubmersible or "jetpumps," which pump water down into the well in order to force water out of the well are also used, as are other types of nonsubmersible pumps.
In a typical system, a pressure tank is used for storing a certain amount of water pumped from the well. The pressure tank is pressurized with air and connected between the pump and the house to provide a reservoir of pressurized water to the house, thereby minimizing the number of pump starts by extending the pump "on" time. The pump (or a pump starter box) is connected to an AC power supply via a mechanical pressure switch working as a control unit. The mechanical pressure switch is also connected to the pressure tank. A pressure gauge connected to the mechanical pressure tank is used to monitor the water pressure coming from the pressure tank. When this water pressure drops below a certain level, the control system activates the pump submerged in the well, which causes additional water to be pumped from the well to the pressure tank.
Pumps used in this manner are vulnerable to many types of problems. For example, if the well runs dry for any reason, the pump will quickly overheat and burn up as it tries to pump nonexistent water to the pressure tank. Similarly, if the pressure tank looses air pressure, a condition referred to as rapid cycle begins in which the pump turns on and off repeatedly over a short period of time. Ideally, the number of pump starts should be limited to about thirty per day and the pump "on" time should be longer than one minute. More than about three hundred starts per day for a three quarter horsepower pump will result in marked deterioration of the pump. Additionally, either undervoltage or overvoltage fluctuations in the AC power supply can cause the pump to burn up.
When a pump burns up, regardless of the reason, the pump has to be replaced. With submersible pumps, pump replacement usually entails digging up the well in addition to acquiring a new pump. Therefore, this is a relatively expensive and time consuming repair.
The pump control system of the present invention minimizes pump problems due to the low water condition, the rapid cycle condition and the undervoltage and overvoltage conditions, and also permits use of a simplified installation process for installing the pump control system.